Such an autoclave is known from EP-B 0 133 239, in which the autoclave casing is made double-wailed in order either that a heated heat carrying material such as hot oil can flow through directly or that it can receive heating coils, through which the heat transfer medium flows. Such autoclave heating is costly in terms of structure and energy, as well as slow.
The object of the invention is to provide an autoclave of the kind initially recited, whose heating is simplified structurally, which is favourable in terms of energy and is easy to control.